The objectives of this proposed research are: (1) investigation of RNA-directed DNA synthesis and the coupled role of DNA polymerase and ribonuclease H activities using purified DNA polymerase and intact 35S RNA from avian myeloblastosis virus; (2) detection and characterization of additional enzymes and factors from virus particles and/or virus-infected cells involved in reverse transcription of viral RNA; and (3) reconstitution of viral RNA-directed DNA complex synthesizing viral DNA analogous to that found in the infected cell.